The present application relates to an electrostatic capacitance-type input device that detects an input position based on a change in the electrostatic capacitance coupled with an input position detecting electrode, a method of testing the electrostatic capacitance-type input device, and a driving device for an electrostatic capacitance-type input device. Among electronic apparatuses such as cellular phones, car navigation systems, personal computers, ticket-vending machines, and banking terminals, there are apparatuses, in which an input device termed a touch panel is arranged on the surface of a liquid crystal device or the like, allowing a user to input information while referring to an image displayed in an image display area of the liquid crystal device. Among such input devices, electrostatic capacitance-type input devices, as schematically shown in FIG. 11, have a plurality of first electrodes 211 that extend in the X direction and are used for detecting an input position, a plurality of second electrodes 212 that extend in the Y direction and are used for detecting an input position, and a plurality of signal wirings 27 that extend from one-side end portions of the first electrodes 211 and one-side end portions of the second electrodes 212 on a substrate 20 and monitor electrostatic capacitance that is coupled with each of the first electrodes 211 and the second electrodes 212 through a signal wiring 27. Thus, when a finger is in proximity to any of the first electrodes 211 and the second electrodes 212, the electrostatic capacitance of the electrode to which the finger is in proximity increases by the amount corresponding to electrostatic capacitance generated between the finger and the electrode. Accordingly, the electrode to which the finger is in proximity can be specified.
In such electrostatic capacitance-type input devices, when a short circuit is formed in one spot in the first electrode 211 or the second electrode 212, it is difficult to detect the input position in the corresponding row. Accordingly, detecting whether a short circuit is formed in the first electrodes 211 and the second electrodes 212 is important in terms of securing the reliability of the electrostatic capacitance-type input devices.
As a method of testing formation of a short circuit in the electrodes, a test method in which a sensor electrode is brought to be in proximity to a plurality of electrodes one after another, and coupled capacitance between the sensor electrode and the corresponding electrode is monitored is proposed (for example, see JP-A-2004-191381).